Electromagnet with two armatures



May 2, 1950 w. A. BEVHS ET AL ELECTROMAGNET WITH TWO ARMATURES Filed Jan. 27, 1945 Patented May 2, 1950 UNITED STATES PATENT OFFICE ELECTROMAGNET WITH TWO ARMATURES Application January 27, 1945, Serial No. 574,913 In Great Britain January 20, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires January 20, 1964 1 Claim.

This invention relates to electromagnetic regulators for controlling the voltage or current output of dynamos, and particularly variable speed dynamos as used on vehicles in conjunction with electric storage batteries. The type of regulator to which the invention relates is that comprising a vibratory armature carrying a contact which co-operates with a stationary contact, the contacts being adapted to control the current through a field winding of the dynamo, and the winding of the regulator magnet being adapted to be responsive to either the dynamo voltage, or the current output of the dynamo. As is well known, there is a limit to the duty which can be imposed on such a regulator, and in consequence it is a known practice to provide the dynamo with two separate field windings and arrange a regulator in association with each, thus dividing the total duty between two regulators. It has been found, however, that this arrangement is not altogether satisfactory. The object of the present invention is to provide an improved regulator which obviates the disadvantages of regulators of ordinary construction.

In the accompanying sheet of explanatory drawings:

Figure 1 is a diagrammatic sectional side elevation of a duplex regulator constructed in accordance with the invention.

Figure 2 is a diagram illustrating the duplex regulator applied to the field system of a dynamo.

In carrying the invention into effect as shown in Figure l, we employ an iron base a on which are secured or formed a pair of cores or pole pieces b extending parallel to each other at right angles to the base, and on each of the pole pieces is mounted an exciting winding 0. These windings are adapted to be responsive to the dynamo voltage or current. Adjacent to and between the outer ends of the two pole pieces 17 is mounted another iron part (1, the latter being supported by the outer end of a non-magnetic support 6 in the form of a post or posts also secured to the base a at a position between the pole pieces. To the iron part are attached preferably by spring blades 1 (but alternatively by any convenient pivotal means) a pair of vibratory iron armatures 1 which extend from opposite sides of the said iron part over the outer ends of the pole pieces I). The armatures I carry contacts 9 adapted to cooperate with adjacent adjustably fixed contacts h. The contacts g, h are adapted for connection to the associated field winding circuits of the dynamo in any convenient and usual manner. The pole pieces b may be supported at their outer ends by any convenient means, such as a fixed 2 insulating plate 2 which may also serve to support brackets 7 carrying the contacts h, the bracket being connected to terminals and the base a being earthed.

From the foregoing it will be apparent that the magnetic flux paths through the two armatures f are in series with each other. In other words, there is a single flux path through the iron base a, the two pole pieces b, the two armatures f, and the iron part (1 between the latter.

A simple mode of applying a duplex regulator as above described to the field system of a dynamo is illustrated by Figure 2 in which m indicates the dynamo armature, n the field windings, o the usual cut-out, and p a battery. The two pairs of regulator contacts 9, h are respectively connected in series with the two field windings n and serve to introduce into or remove from the circuits of these windings resistances q which may be wound as bucking coils on the same cores as the regulator windings c. The latter are connected in series with each other across the dynamo armature m and act together in response to the dynamo voltage. Due to the single flux path above mentioned, the duty of the regulator is shared equally by the two pairs of contacts 9, it.

By means of a duplex regulator for controlling two field windings and having the fiux paths of the two armatures in series as above described, we are able to obtain the desired regulation in a satisfactory manner. The invention is not, however, restricted to the example above described as details of design or construction may be varied to suit difierent requirements.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

A duplex electromagnetic device having only a single closed magnetic circuit, the magnetic elements thereof consisting of an iron base, a pair of iron pole pieces extending parallel to each other from one side of said base, an iron part fixedly arranged between those ends of the pole pieces remote from said base, and a pair of independently movable vibratory armatures connected to opposite sides of said iron part and extending in opposite directions therefrom over the said ends of the pole pieces; and exciting windings on the respective pole pieces, whereby the armatures form with the pole pieces, the base and the said iron part a single path for the magnetic flux created in the pole pieces by energization of the windings.

WILLIAM ALBERT BEVIS. ALBERT VICTOR WATERS.

(References on following page) 3 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Number Name Date Smith Apr. 9, 1912 Moses Dec. 28, 1920 Thompson Mar. 26, 1929 Horn Sept. 20, 1932 FOREIGN PATENTS Country Date Great Britain Feb. 1, 1923 

